Twenty years ago, if you wanted to drive out for a trip, most of the co-pilots needed to hold a traffic atlas to direct the driver. Today, a mobile phone can meet this demand and provide lane-level precise positioning, thanks to the mobile phone equipped with a satellite navigation receiving chip.
The Beidou system is one of the four major navigation systems in the world and is a satellite system independently developed by the mainland. In addition to doing a good job of "navigation", Beidou plays an important role in agricultural production, emergency rescue and disaster relief.
In Anzhong Village, Xiaoyangying Township, Dengzhou City, Henan Province, a tractor equipped with a Beidou navigation system sows seeds unmanned (drone photo taken on May 26, 2020). Photo by Xinhua News Agency reporter Feng Dapeng
However, the construction of the Beidou system has not been smooth sailing. It was not until today, 17 years ago, that the first satellite of Beidou-2 transmitted the first set of signals back to win the frequency defense war. What kind of history is this? Regarding the development of the Beidou system, we must start with the Gulf War at the end of the last century.
"No matter how poor you are, you have to build your own satellite navigation system"
In 1991, GPS was first applied in the Gulf War, and it was an instant hit. The summary report of the Gulf War even attributed the war to a "victory of the GPS", saying that it was a "multiplier of military power." After the Gulf War, countries realized the military importance of satellite navigation systems.
On July 23, 1993, due to a diplomatic conflict, the United States abruptly turned off the GPS signal of the Chinese freighter "Yinhe", resulting in the Yinhe being forced to suspend normal shipping and drift for 33 days. During this period, there were many hardships.
The Chinese realize that they must build their own satellite navigation system in order to no longer be constrained by other countries. Academician Sun Jiadong and Shen Rongjun, deputy director of the Commission of Science, Technology and Industry for National Defense, jointly suggested that China's satellite navigation project be launched.
In December 1994, the Beidou Navigation Experimental Satellite System project was approved by the state.
China has divided the construction of its satellite navigation system into "three steps": the first step is to cover the country, the second step is to cover the Asia-Pacific region, and the third step is to cover the whole world.
This is the origin of Beidou-1, Beidou-2, and Beidou-3.
Beidou-1 system, from scratch
On October 31, 2000, the first Beidou navigation test satellite developed by the mainland was successfully launched into space.
In the early morning of October 31, 2000, China's first self-developed navigation and positioning satellite, the "Beidou Navigation Test Satellite," was launched from the Xichang Satellite Launch Center and successfully entered the scheduled orbit. Photo by Xinhua News Agency reporter Zha Chunming
In less than two months, the China Aerospace Science and Technology Corporation (CASC) successfully launched the second Beidou navigation test satellite into space orbit. On May 25, 2003, the third Beidou satellite was launched and deployed.
Since then, the Beidou satellite navigation test system has been built, which is Beidou-1.
The successful advent of the Beidou-1 system has made China the third country in the world to have an autonomous satellite navigation system after the GPS of the United States and GLONASS of Russia.
BDS-1 also has a unique short message function in the field of international navigation.
The Wenchuan earthquake in 2008 also disrupted roads, electricity, and communications, and the hardest-hit areas lost all contact with the outside world. The short message communication function of the Beidou Navigation Satellite System has played a great role. According to statistics, during the rescue period, the search and rescue forces sent 740,000 text messages with Beidou.
"The 'giants' blocked our technology and didn't let us stand on our shoulders, and the only way was to become giants ourselves. Li Zuhong, commander-in-chief of the Beidou-1 satellite, said.
The Beidou-1 system has enabled China's own satellite navigation system to achieve a huge leap from scratch.
Win the battle to defend the frequency
Any country that wants to develop its own satellite navigation system must first apply to the International Telecommunication Union (ITU) for frequencies. At that time, the most suitable golden frequency band for satellite navigation had been fully occupied by the United States and Russia.
China can only compete with the EU for the same frequency. This small frequency band, which is only a quarter of the golden band, is the most basic frequency requirement for the construction of a global satellite navigation system.
On 17 April 2000, China submitted a band application to the International Telecommunication Union, and on 5 June 2000, the European Union's Galileo satellite navigation system also submitted a band application.
With regard to frequency applications, the International Telecommunication Union has two rules: "first-served" and "late-expired".
"Expired invalidation" means that the validity period of the frequency is calculated from the date of application, and the application will be invalidated if it is not successfully used within 7 years. Therefore, China's first Beidou-2 satellite must be successfully launched and broadcast before midnight on April 18, 2007, otherwise it will be "overdue".
And because there is a high degree of overlap in the frequencies applied by China and the EU, the two sides need to compete, and whoever sends the satellite first and successfully broadcasts the signal will get the right to use this frequency - this is "first come, first served".
China applied for this frequency earlier, but it started late, Beidou-2 only started in 2004, losing the EU Galileo system at the starting line for 2 years.
Beidou staff worked overtime to complete all the research and development work in a race against time. After that, all the staff were stationed in the Xichang Satellite Launch Center together, installing equipment, carrying cabinets, and laying cables.
On April 14, 2007, the first Beidou-2 satellite was successfully launched into space.
At 4:11 a.m. on April 14, 2007, the mainland successfully launched a Beidou navigation satellite into space with the Long March-3A carrier rocket at the Xichang Satellite Launch Center. Photo by Xinhua News Agency reporter Li Gang
Three days later, at 20 o'clock on April 17, 2007, the satellite successfully sent the first set of signals, which means that China has officially activated the declared frequency resources. At this point, there are only 4 hours left before the "overdue expiration" point in time.
On this day, China not only successfully won the frequency defense war, but also officially opened the prelude to the construction of the Beidou regional navigation system.
On December 27, 2012, the Beidou Navigation Satellite System officially provided regional services, realizing all-day and all-weather positioning, navigation and timing services for most parts of the Asia-Pacific region.
The application of Beidou is limited only by imagination
The completion of Beidou-2 has brought China's own satellite navigation system to a level consistent with international advancement. Standing on the shoulders of the first two generations of constellations, Beidou's third step towards globalization is very stable.
On March 30, 2015, the first Beidou-3 test satellite was successfully launched.
On November 5, 2017, the Beidou-3 global networking twin satellites were launched for the first time.
Throughout 2018, Beidou launched a total of 18 satellites, setting a world record.
On December 27, 2018, the BDS-3 basic system was completed and began to provide global services.
On June 23, 2020, with the loud sound of a tsunami in the mountains, the Long March rocket with a dazzling white tail flame at the bottom took off, sending the last global networking satellite of Beidou-3 into space. So far, China has completed the deployment of the Beidou global navigation satellite system constellation half a year ahead of schedule.
On June 23, the last networked satellite of the mainland's Beidou-3 global navigation satellite system was ignited at the Xichang Satellite Launch Center. Photo by Xinhua News Agency reporter Jiang Hongjing
Today, the services of the Beidou Navigation Satellite System have benefited the world.
More than 70% of the smartphones connected to the network in China provide Beidou services, and e-commerce, mobile intelligent terminal production, location services, etc. based on Beidou navigation services have also widely entered our consumption, economy and life.
A large lightship using a Beidou buoy telemetry remote control device is launched on the Dangan Waterway at the Pearl River Estuary (photo taken on June 20, 2019). Photo by Xinhua News Agency reporter Tian Jianchuan
On April 9, 2020, a tractor equipped with a Beidou navigation system manages rice on autopilot at the Smart Agricultural Science and Technology Demonstration Zone in Tawan Village, Jinji Town, Litong District, Wuzhong City, Ningxia Province (drone photo). Photo by Xinhua News Agency reporter Feng Kaihua
Worldwide, more than half of the countries are already using the Beidou system. Pakistan's transportation and port management, Myanmar's land planning and river transportation supervision, Laos's precision agriculture and pest and disease disaster supervision, Brunei's urban modernization and smart tourism, Indonesia's maritime integrated applications, as well as Saudi Arabia, the United Arab Emirates, Egypt, Tunisia, Algeria and other countries......
Based on Beidou, China has built a modern space Silk Road.
"The application of Beidou is only limited by imagination. This is the rhetoric of tens of thousands of Beidou people, and it is also the future of Beidou.
Source: Popular Science China